Unit VIII - Ear Pt. 2

Question 1

What SURROUNDS the membranous labyrinth?

Answer 1

Perilymph within the bony labyrinth

Question 2

What is another name for the inner ear?

Answer 2

Labyrinth

Question 3

What are the parts of the bony labyrinth?

Answer 3

Cochlea, vestibule, semicircular canals

Question 4

What is the shape of the cochlea, and what does it contain?

Answer 4

Snail shell shaped; contains cochlear duct

Question 5

What is contained in the vestibule?

Answer 5

Utricle and saccule

Question 6

What do the lateral, anterior, and posterior semicircular canals contain?

Answer 6

Semicircular ducts

Question 7

What fluid is located WITHIN the membranous labyrinth?

Answer 7

Endolymph

Question 8

The utricosaccular duct is located between what two structures?

Answer 8

Utricle and saccule

Question 9

What structures are found in the vestibular labyrinth?

Answer 9

Utricle, saccule, semicircular ducts, utricosaccular duct, endolymphatic duct and sac, ductus reuniens

Question 10

What is the cone-shaped central bony structure that the cochlea wraps around 2.5 to 2.75 times?

Answer 10

Modiolus

Question 11

What is the name of the apex of the cochlea?

Answer 11

Cochlear cupula

Question 12

The cochlear cupula lies in what direction?

Answer 12

Anterolaterally

Question 13

What is the bony ridge that connects the cochlea to the modiolus?

Answer 13

Lamina of the modiolus

Question 14

What three channels make up the cochlea?

Answer 14

Cochlear duct, scala vestibuli, scala tympani

Question 15

Where does the cochlear duct end?

Answer 15

Apex of cochlea

Question 16

How do the scala vestibuli and scala tympani communicate?

Answer 16

At the apex through a channel called the helicotrema

Question 17

What fluid fills the scala vestibuli?

Answer 17

Perilymph

Question 18

As the stapes vibrates, where are the vibrations transmitted?

Answer 18

Into the scala vestibuli

Question 19

Which structure is located above the cochlear duct: scala vestibuli or scala tympani?

Answer 19

Scala vestibuli

Question 20

Which structure is located below the cochlear duct: scala vestibuli or scala tympani?

Answer 20

Scala tympani

Question 21

How do vibrations that are transmitted through the scala vestibuli pass to the scala typani?

Answer 21

Via the helicotrema

Question 22

What is the base of the scala tympani?

Answer 22

Round window

Question 23

What forms the base of the scala vestibuli?

Answer 23

Oval window

Question 24

Where is the cochlear duct located and what is found above and below it?

Answer 24

Middle of the bony labyrinth with scala vestibuli above and scala tympani below

Question 25

What fills the cochlear duct?

Answer 25

Endolymph

Question 26

The cochlear duct is attached to what structure?

Answer 26

Lamina of the modiolus

Question 27

What anchors the cochlear duct to the outer wall of the cochlea?

Answer 27

Spiral ligament

Question 28

What separates the cochlear duct from the scala vestibuli?

Answer 28

Vestibular membrane

Question 29

What separates the cochlear duct from the scala tympani?

Answer 29

Basilar/spiral membrane

Question 30

Where is the spiral organ located, and what is it attached to?

Answer 30

On the floor of the cochlear duct; attached to basilar/spiral membrane

Question 31

What is the purpose of the numerous hair-like projections that project superiorward from the basilar/spiral membrane of the spiral organ?

Answer 31

They are sensitive to frequency and amplitude of sound waves that enter the cochlea

Question 32

What covers the hair cells seen in the spiral organ?

Answer 32

Tectorial membrane

Question 33

Where are the cell bodies located for the primary sensory neurons of the spiral organ that receive information from the receptor cells?

Answer 33

Spiral ganglion

Question 34

When sound waves enter the external acoustic meatus, what structure vibrates?

Answer 34

Tympanic membrane

Question 35

What structures transmit the vibrations from the tympanic membrane?

Answer 35

Ossicles of the middle ear (malleus, incus, and stapes, in that order)

Question 36

What process amplifies the vibrations 1.2 times?

Answer 36

Transmission of vibrations through middle ear ossicles

Question 37

What is the reason that vibrations that enter the external acoustic meatus are amplified another 17 times?

Answer 37

The oval window diameter is much smaller than the tympanic membrane

Question 38

The foot of which ossicle articulates with the oval window?

Answer 38

Stapes

Question 39

What forms the base of the scala vestibuli?

Answer 39

Oval window

Question 40

After the vibrations are transmitted through the ossicles, where are they then transmitted?

Answer 40

Through the perilymph of the scala vestibuli and the scala tympani, eventually reaching the round window

Question 41

After the vibrations are transmitted through the perilymph, what structure vibrates, and what is the result?

Answer 41

Basilar membrane; stimulation of receptors in the spiral organ

Question 42

After the receptors in the spiral organ are stimulated, where is the information then transmitted?

Answer 42

To the cochlear nerve

Question 43

What fluid is contained in the saccule, utricle, and three semicircular ducts?

Answer 43

Endolymph

Question 44

What are the three semicircular ducts?

Answer 44

Anterior, lateral, posterior

Question 45

What does the saccule communicate with?

Answer 45

Cochlear duct

Question 46

Which is larger: saccule or utricle?

Answer 46

Utricle

Question 47

What does the utricle communicate with?

Answer 47

All three semicircular ducts and the saccule

Question 48

How does the utricle communicate with the saccule?

Answer 48

Utricosaccular duct

Question 49

What are the sense organs within the utricle and saccule?

Answer 49

Hairlike projections called maculae

Question 50

What bathes the maculae?

Answer 50

Endolymph

Question 51

What tiny structures float on the endolymph that bathes the maculae?

Answer 51

Otoliths

Question 52

What kind of action causes the otoliths to deflect the maculae and thus elicit impulses?

Answer 52

Movements of the head

Question 53

Which detects centrifugal and linear in any direction accelerations: utricle or saccule?

Answer 53

Utricle

Question 54

Which detects linear accelerations: utricle or saccule?

Answer 54

Saccule

Question 55

What are the sense organs located within the semicircular ducts?

Answer 55

Crista

Question 56

Where are the crista located in the semicircular ducts?

Answer 56

In the ampulla of each duct

Question 57

What movements are the semicircular ducts sensitive to?

Answer 57

Accelerations in any direction, but particularly sensitive to rotational accelerations

Question 58

Where are the cell bodies located for the neurons that carry information from the impulses that are initiated by the sense organs of the vestibular labyrinth (maculae and crista)?

Answer 58

Vestibular ganglion

Question 59

What are the two branches in which the dendrites carrying information to the vestibular ganglion are collected in?

Answer 59

Superior and inferior branch

Question 60

Which branch carrying information to the vestibular ganglion is larger?

Answer 60

Superior branch

Question 61

Which branch to the vestibular ganglion carries information from the anterior and lateral semicircular ducts, utricle, and some from the saccule?

Answer 61

Superior branch

Question 62

Through what nerve is information carried from the saccule to the superior branch?

Answer 62

Voit's nerve

Question 63

The inferior branch to the vestibular ganglion carries information from where?

Answer 63

Posterior semicircular duct and saccule

Question 64

What nerve is made up of axons from the vestibular ganglion?

Answer 64

Vestibular nerve

Question 65

What makes up the blood supply to the labyrinth?

Answer 65

Internal auditor artery, a branch from the basilar artery | Stylomastoid artery, a branch from the posterior auricular artery

Question 66

What makes up the nerve supply to the labyrinth?

Answer 66

Sympathetics from cavernous and/or internal carotid plexuses Cochlear nerve Vestibular nerve

Question 67

The cochlear nerve is composed of axons of cells from where?

Answer 67

Spiral ganglion

Question 68

What is the pathway of information through the cochlear nerve?

Answer 68

Cochlear nuclei --> superior olivary and trapezoid nuclei in medulla oblongata --> lateral lemniscus --> inferior colliculi and medial geniculate bodies --> temporal lobe (Bdmn. areas 41 and 42)

Question 69

The vestibular nerve is composed of axons from where?

Answer 69

Vestibular ganglion

Question 70

What is the pathway of information through the vestibular nerve?

Answer 70

Vestibular nuclear complex of medulla oblongata --> processed in cerebellum